The idea just came to me as I was day dreaming. A game where you play as a fish wanting to fly. It would be an endless runner where you hold down a key to dive, the deeper you dive the higher you jump through the sky. Avoid obstacles, collect bonus points, etc.
Referencing other games, the best way I can explain it is something similar to Halfbrick's Jetpack Joyride.
As a relative beginner without great equipment I think that this is a project with reasonable scope and is something I feel is achievable.
Obstacles I foresee are (1) creating and tweaking acceleration to feel good and intuitive, and (2) level design/procedural generation. Addressing these:
(1) I'd like to study Jetpack Joyride's movement as I remember it feeling just right, and see how this can apply to my game
(2) I think that full level design is unfeasible and limiting. I plan to create 'modules' of obstacles and awards which can randomly appear one after the other. The modules which appear can be decided based on the player's current score.
Time taken: 1.5 hours
Movement done but no acceleration